Rails initialization from yml configurations

Rails' startup initialization may read configurations from yml files.  For example, on development environment, developers may want exception notifications only be send to himself/herself.

So, developer may create a /config/config.yml (if not exists) for local development while commits a /config/config.yml.example for source control.  Then in config.yml, create a section like:

development:
    exception_email_recipient: someone@example.com

Next, in /config/initializers/exception_notification.rb, read the config from yml, like this:

filepath = "#{Rails.root.to_s}/config/config.yml"
local_config = YAML.load_file(filepath)
exception_email_to = local_config[Rails.env]['exception_notification_email_to']

Merlot::Application.config.middleware.use ExceptionNotifier,
    :email_prefix => "[Project_name][#{Socket.gethostname}] ",
    :sender_address => %{"Exception" <exception@example.com>},
    :exception_recipients => [ exception_email_to || 'production_recipient@example.com' ]

In this way, on exception emails goes to 'someone@example.com' on development platform.  While on production, it will goes to 'production_recipient@example.com'.